摘要
This paper presents a 155Mbps limiting amplifier for STM-1 systems of SDH optical communication. It is implemented in CSMC 0.5μm CMOS technology. Under a supply voltage of 3.3V, it has a power consumption of 198mW. The core of the circuit is composed of 6 cascaded amplifiers that are in a conventional structure of differential pairs,an output buffer, and a DC offset cancellation feedback loop. The small signal gain can be adjusted from 74 to 44dB by an off-chip resistor. The chip was packaged before being tested. The experimental results indicate that the circuit has an input dynamic range of 54dB and provides a single-ended output swing of 950mV. Its output eye diagram remains satisfactory when the pseudo-random bit sequence （PRBS） input speed reaches 400Mbps.
描述了用于SDH光纤通信STM-1速率级光接收机主放大器的155Mbps限幅放大器．该电路采用CSMC0.5μm CMOS工艺实现，供电电压为3．3V，功耗为198mW．核心电路包含6级级联的传统差分放大器，一个输出缓冲和一个直流失调补偿反馈环路．通过调整片外电阻Rset，小信号增益在44～74dB范围内可调．芯片封装后测试得到的输入动态范围为54dB（Rset=50Ω），单端输出摆幅为950mV，在高达400Mbps伪随机码输入时，所得眼图仍然令人满意。
